Runed
by ncistatelover
Summary: Although Tony may not know it, he is surrounded by Shadowhunters, and they are closer to him than he may think. One little investigation and he finds himself slowly being dragged into their world, pushing his relationships with his friends, teammates and girlfriend to the limits. To mend these relationships, he must learn to accept his true heritage, and that of those around him...
1. Prologue: Parabatai

_While most of New York was dead to the world- sleeping soundly under the serene 1 AM moonlight, there was one area of the city in particular that was completely alive and bursting with action._

 _The girl with unruly chestnut curls whipped around, plunging a blazing seraph blade into the revolting flesh of demon facing her, black blood spraying and sizzling on her indestructible shadowhunter gear. Pure adrenaline was rushing through her veins, and in her head, the voice of fear was completely silent; she was a shadowhunter, and this is what she was born to do. The ruby suspended on a chain around her neck pulsed repeatedly, warning of oncoming demon presence, and just as that creature had been banished back to whatever hell it'd come from, another appeared behind her screeching an unearthly screech. Her also fearless Parabatai was on it in a second, instantly covering her back, like she had many times before in battle, and in life in general._

 _These were only lesser demons, which were usually a breeze to destroy, but there was a whole hoard of them in an enclosed space, making them a pain in the ass to dispose of: as soon as you'd gotten rid of one, another one would appear seemingly out of nowhere and attack you from a different angle, leaving no time to pause in between. Not that she needed to pause, obviously._

 _As she was pounced on by yet another demon, she noticed her partner hurl a dagger at one demon while stabbing at another simultaneously with a long blade. The dagger sailed soundly across the alleyway that they were battling in and embedded itself right in the centre of the beast's chest. The demon flailed angrily, hissing like an enormous cobra as it did so, and spat venom from its deadly mouth as it did so. She heard her Parabatai curse loudly and dodge out of the way as some of the venom spattered onto her forearm, before finishing off the creature that she was directly battling with a swipe of her blade._

 _The girl slashed at a nearby demon with her electrum whip, severing its ferocious head with a single flick of the wrist. Her ruby pendant stopped pulsing shortly after. She observed the alley briefly, checking for any other signs of hellish life, and, after determining it clear, she headed over to check on her Parabatai, who was using her stele to draw an iratze on the patch where the inchor had splashed on an exposed patch on her arm._

" _That's the last of them," her partner said, finishing the rune with a curve of the stele and giving her a grin. Her partner may look delicate on the outside- she was small and slender with hazel eyes that twinkled as the 2 AM moonlight reflected in them and her dyed chocolate hair was streaked with a golden blond in places where her natural colour shone through, but anyone who knew her and her heritage knew that she was just as strong as any man, perhaps stronger. This didn't stop many guys from gazing after her though, which she often used to her advantage. "Not too bad, Lightwood."_

 _The girl grinned back, pulling her hair out of its messy fighting braid and letting her curls loose on her shoulders. "Same back to you, Herondale." She leaned back against the wall next to her sworn sister, and gazed up at the stars. Unlike her partner, she had dark chocolate eyes and wild, untameable hair that barely stayed where it was put for 5 minutes at a time, proving to be rather difficult during fights. She knew for a fact that she got it from her father, just like most of her looks. It was at times like this where she was jealous of her mother, who had long black hair that could be slicked right back and would stay there for hours._

" _Well," said her partner, moving away from the wall and sheathing her blades, "I bid you goodnight my sister, and I'll meet you back at the Institute usual time, unless my work prevents me from doing so."_

" _Me too my friend, me too," the girl replied with a smile._

 _With a final nod, the Herondale turned on her heel and disappeared down alleyway, the black marks covering her body standing out against her tan skin boldly and brilliantly in the night._

* * *

 **A/N: Since I know that I will get a few questions about this, here are a few disclaimers:**

 **-Whether NCIS is set later or TMI was set earlier is the reader's decision.**

 **-This is set in late NCIS season 2, and long after TMI finished.**

 **-I don't own either of these franchises.**

 **I hope you enjoy this new crossover fic, I'm certainly enjoying writing it!**

 **Louise :)**


	2. Chapter 1: Black Marks

"Katie?" Tony called gently, perching on the end of the bed that they'd been sharing for the past couple of months and shaking her softly, "Time to get up."

Kate always struggled to get up in the mornings, no matter what time she'd fallen asleep the night before. It didn't make a difference if she went to bed at 7 PM or 11 PM, she was always exhausted when 6 AM came and she was forced to awaken in order to get to work on time. Tony waking his girlfriend up rather than the alarm clock doing so was becoming a rather regular occurrence in their small household, but he didn't particularly mind. Not that anyone knew this, of course.

In fact, nobody knew that they were even an item: they'd managed to keep their almost-2-month-long romance on the down low, so not one of their teammates at NCIS knew the slightest thing about it. It was definitely for the best- they were breaking one of their boss' most sacred rules, and were most likely to get fired or moved to a different team if they were found out. Normally, Kate wasn't one for breaking rules, but when it came to Tony, she couldn't help but break rule #12, especially after what their trip to Paraguay had helped them both realise.

When Kate didn't awaken, Tony slowly leant down and placed a light kiss on her cheek. At this, her eyes fluttered open groggily, adjusting to the light that the early morning sun was sending through the slightly open apartment windows. When she saw her partner leaning over her, she smiled sleepily.

"Rise and shine gorgeous," Tony grinned back, brushing a lock of her dark hair off her face and behind her ear.

"Morning Tony," she yawned, sitting up hesitantly and leaning back against her pillow tiredly. Tony couldn't help but notice that she was gripping the sleeve of her pyjama top tightly, as if she was holding the sleeve down forcefully. He wouldn't have thought twice about it if he hadn't seen what she looked like beneath it, covered with silvery white scars that he couldn't describe, that were all sorts of exotic shapes. The amount of them that she had seemed to increase almost daily and they covered her like a sheet, mostly along the arms and legs. However, whenever he tried to ask where they came from, she either ignored him, brushed his questions away by changing the subject or danced around them skilfully. He had no idea where they came from, but he knew that he was going to find out at some point, whether she wanted him to or not.

Since he was already washed and dressed ready for work, he shifted over so that he was beside her and wrapped his arm around her back as she downed the steaming mug of coffee that he'd placed on the dresser for her. The beverage was scolding hot, but she didn't flinch as she drained the mug in under a minute. Once it was gone, she planted a kiss on the tip of his nose, placed empty mug back on the dresser, picked out an outfit from the closet and headed for the bathroom.

Half an hour later, Kate emerged from the bathroom, freshly washed; make up done and wearing one of her typical work outfits. Once again, Tony couldn't help but realise that she was wearing a long sleeved top, even though it was positively warm today. While she was making a last minute breakfast- oatmeal and assorted fruit, he ambled up behind her and wrapped his arms around her waist. He smiled as she instantly relaxed against him, taking his hands in hers.

"You alright?" She giggled softly as he planted a small kiss on the star shaped mark on her shoulder. The mark that was unique to her and her heritage.

"Perfect," he smirked against her skin before pulling away. She shivered and ran her hands up her arms as he turned and walked towards the kitchen door. Tony watched as her sleeves slid up her arms and gaped at what he saw.

On her right forearm was a large, faded grey mark, in an ancient looking shape that had no meaning to him. It looked like some kind of tattoo, but he knew that tattoos didn't fade like that, and there was something in the blood pulsing through his veins that told him that this was no ordinary mark. Before he could take a closer look however, Kate hastily pulled her sleeves back down, and continued on making breakfast.

Though he was confused at what he saw, Tony made an observation; one that he was to prove and investigate.

Kate was hiding something from him, and he was going to find out what it was.


End file.
